1. Technical Field
This disclosure relates to an organic thin-film transistor having an organic semiconductive layer.
2. Discussion of the Related Art
Recently, research and development of organic thin-film transistors using organic semiconductive materials has become popular. Thin films of the organic semiconductive materials can easily be formed simple wet process methods such as printing method and spin coat method. Compared with conventional thin-film transistors using inorganic semiconductive materials, it is advantageous that the organic thin-film transistors can be prepared at a low temperature. Therefore, the organic thin-film transistors can be formed on a plastic board typically having low heat resistance. Then, the weight and cost of electronics devices such as a display can be saved and various applications such as applications taking advantage of the flexibility of the plastic board can be expected.
Japanese Published Unexamined Patent Application No. 5-55568 discloses acene materials such pentacene as the organic semiconductive materials. Although an organic thin-film transistor using the pentacene as the organic semiconductive layer is reported to have comparatively a high transportability, the acene materials have extremely low solubility in generic solvents and need to be subjected to a vacuum deposition process when thinned as the organic semiconductive layer in the organic thin-film transistor. Therefore, this is not as simple as the methods such as printing method and spin coat method mentioned above.
Japanese Published Unexamined Patent Applications Nos. 2005-101493 and 2005-154709 disclose an organic thin-film transistor having an organic semiconductive layer formed of polyarylenevinylene including a site of a triarylamine structure. Having high solubility in the organic solvent, the polyarylenevinylene including a site of a triarylamine structure can form an organic semiconductor with simple printing processes such as inkjet printing, spin coat and gravure printing. In addition, since the polyarylenevinylene including a site of a triarylamine structure forms a uniform coated film, the resultant organic thin-film transistors have less piece-to-piece variations when having a larger area, which is expected therefor. However, the carrier transportability needs to be further increased, which is required for the organic thin-film transistors.
Because of these reasons, a need exists for an organic thin-film transistor having high transportability, which can be prepared simple processes such as coating and printing.